When a man marries a princess or a queen, does he take his wife's rank?
When a man marries a princess or a queen, he does not take his wife's rank and become automatically a prince or a king. In (English) common law a man retains his name upon marriage.
Conversely, when a woman marries a prince or a king, she becomes automatically a princess or a queen; this is in keeping with (English) common Law whereby a woman is entitled to her husband's name.
If the husband of a queen were permitted to be known as king, he would then technically rank higher than his wife the queen.
The husband of a princess or a queen can have a peerage or a title conferred upon him by the Sovereign. ]
Three examples when a peerage or a title was bestowed on the spouse of a princess or a queen 1961: when Antony Armstrong-Jones, husband of HRH Princess Margaret, was created a peer when he was made Earl of Snowdon on 6 October 1961 (Antony and Margaret had been married since 6 May 1960)
1947: when Lieutenant Philip Mountbatten, husband of HRH Princess Elizabeth (later Queen Elizabeth II), was created a peer when he was made Duke of Edinburgh on 20 November 1947 the day of his wedding (N.B.: Philip received the style Royal Highness the day before on 19 November, and was made a Prince of the United Kingdom of Great Britain and Northern Ireland on 22 February 1957)#
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1857: when Prince Albert of Saxe-Coburg and Gotha, husband of Queen Victoria, was granted the title Prince Consort on 26 June 1857 (N.B.: Albert received the style Royal Highness on 6 February 1840 four days before his marriage)
It is worth noting that the British Constitution does not make any provision for the position of a husband to a Queen (see the question:A man who marries a princess who later becomes queen or who marries a queen regnant, does not become king. Queen Victoria succinctly summarized the situation: 'It is a strange omission in our Constitution that while the wife of a King has the highest rank and dignity in the realm after her husband assigned to her by law, the husband of a Queen regnant is entirely ignored by the law
When a woman marries a prince, why does she use her husband's Christian name in her title instead of her own name?
The wife of a prince takes her husband's Christian name in her title as do all married royal women. This is because it is the correct style for any married woman ('Mrs' followed by her husband's Christian name and then his surname.) When a woman is known as 'HRH Princess [her Christian name] of [Gloucester, or Great Britain, or Kent, or York, etc...]', this indicates she is a princess
by birth. When a woman is known as 'HRH Princess [her husband's Christian name] of [Gloucester, or Great Britain, or Kent, or York, etc...]', this indicates she is a princess
by marriage. That is why it is correct for the former Baroness Marie-Christine von Reibnitz to be known as 'HRH Princess Michael of Kent' instead of being known as 'HRH Princess Marie-Christine of Kent'.
The situation is slightly different when a woman is married to a prince who happens to be a royal duke or the Prince of Wales. When a woman is married to a royal duke she is known, for example, as 'HRH The Duchess of Kent', not 'HRH Duchess [her husband's or her Christian name] of Kent'. When a woman is married to the Prince of Wales, she is known as 'HRH The Princess of Wales', not 'HRH Princess [her husband's or her Christian name] of Wales'.
The ways of addressing royal women change once there is a divorce. In the case of the late Diana, Princess of Wales, Diana was entitled to 'HRH The Princess of Wales' while she and Charles were married. Following her divorce, Diana ceased to be both a Royal Highness and a princess because she was no longer married to a Royal Highness and prince. (
These were hers only by marriage not by birthright.) Accordingly, Diana became known by the name 'Diana, Princess of Wales'.
In the case of Sarah, Duchess of York she was entitled to be known as 'HRH The Duchess of York' while she and Andrew were married. Following her divorce, she too ceased to be both a Royal Highness and a princess because she was no longer married to a Royal Highness and a prince. (Again,
these were hers only by marriage not by birthright.) Sarah is therefore known by the name 'Sarah, Duchess of York'.
This style is common to divorced wives of British peers which was the situation in which Diana and Sarah were in August and May 1996, respectively. (Note, however, that Sarah is not addressed as 'Your Grace'